The present status of heavy element nuclear chemistry research at JAERI (Japan Atomic Energy Research Institute) is reviewed. Successful production of the transactinide nuclei, ²⁶¹Rf and ²⁶²Db via the reactions of ²⁴⁸Cm (¹⁸O, 5n) and ²⁴⁸Cm (¹⁹F, 5n), respectively at the JAERI tandem accelerator is presented. Aqueous chemistry of Rf is being carried out with a newly developed rapid ion-exchange separation apparatus. Anion-exchange behavior of Rf in HCl solution is shortly discussed. Recent experimental results on decay studies of neutron-deficient actinide nuclei using the gas-jet coupled JAERI-ISOL are also given. Prospects for the near future studies are briefly considered.